This invention relates to indicating light units, especially for motor vehicles.
It is known from European patent specification No. EP 0 211 742 B1 to provide an indicating light unit for a motor vehicle, comprising a light source and a dividing screen which is adapted to divide the light beam emitted from the light source into two sets of elementary beams, in such a way that these two sets of beams are then added together downstream of the dividing screen. This screen comprises two sets of color filters of two different colors, which are adapted to color the respective sets of elementary beams in these two colors. The addition of the two sets of elementary beams, thus colored separately, produces by additive synthesis an emergent beam in a color which is appropriate to the particular function that the indicator light is to serve. This color is different from that of the divider screen when the light is extinguished, which can be of advantage as regards the appearance of the vehicle. However, such a light unit has the disadvantage that manufacture of the screen with the dividing and coloring surfaces is difficult and expensive.
In addition, the ways in which the dividing and coloring surfaces can be arranged are limited, which in turn severely limits the scope for adapting the appearance of the extinguished light to the styling of the vehicle.
An object of the invention is to provide an indicating light unit which will be easier to make, and less expensive, and which further offers the possibility of adapting the appearance of the extinguished light to that of the vehicle.
According to the invention, a indicating light unit, especially for a motor vehicle, which includes a divider screen adapted to divide a light beam into a plurality of elementary beams which are added together again downstream of the divider screen, and a first coloring means adapted to color some of the elementary beams and lying at a distance from the divider screen, is characterised in that it includes a second coloring means adapted to color at least some of the elementary beams and lying at a distance from the divider screen and the first coloring means.
Thus it is possible to manufacture separately, firstly the second coloring means, and secondly the dividing screen and the first coloring means. They are thus easier and less expensive to make. In addition, the scope for providing different arrangements of the dividing and coloring surfaces on these elements in different ways is increased. This then offers further advantages with regard to adapting the appearance of the extinguished light to the styling of the vehicle. One of the coloring means could for example be situated upstream with respect to the other optical elements of the light unit, so that it can hardly be seen from the outside when the light is extinguished.
The second coloring means are preferably upstream of the first coloring means.
Preferably, the second coloring means is upstream of the divider screen.
Preferably, the second coloring means comprises a uniform monochrome colored screen.
Thus, the second coloring means is particularly simple and inexpensive to make.
In addition, some of the elementary light beams are colored at the same time by the first coloring means and the second coloring means in a subtractive synthesis process. The emergent beam is therefore totally produced in accordance with a subtractive-additive synthesis technique. Such a technique enables a suitable color to be obtained in the emergent beam of the light unit. In addition, the second coloring means increases the scope for choice as to how the coloring surfaces are arranged, and for choice of the colors used for the various coloring means so as to give an appropriate appearance to the extinguished light. Thus the scope for adaptation of the appearance of the extinguished light to the styling of the vehicle is increased even more.
Preferably, the second coloring means is adapted to collimate the beam emitted by the light source. Thus, the second coloring means has a double function. It may for example consist of a bonnet.
The first coloring means preferably comprises filters of a first color and filters of a second color, adapted to color the respective elementary beams.
Preferably, the first coloring means is adapted to leave unchanged the color of some of the elementary beams passing through it. In this way the number of colors to be used in the manufacture of the first coloring means is reduced. If this manufacture includes a moulding step, the cost of the tooling is reduced.
Preferably, the first coloring means comprises uncolored filters and a junction portion which is integral with the uncolored filters. With this feature, the presence of the junction portion facilitates manufacture of the first coloring means by moulding. In particular, the uncolored filters can be made in a single injection, through a single feed common to all of the filters. The structure of the mould is thus simplified.
The junction portion preferably comprises a layer which lies in a general plane at right angles to a general direction of propagation of the elementary beams. Manufacture of the junction portion is therefore particularly simple.
The said layer preferably extends along a face of the first coloring means.
The light unit may include first and second light sources associated with a divider screen, the first coloring means being associated with both light sources, and the second coloring means being associated only with the first light source. Accordingly, although the light unit is able to provide two different indicating functions associated with the two light sources, the first coloring means gives a uniform appearance to the extinguished light unit.
In some embodiments, the light unit further includes a third coloring means adapted to color the elementary beams from the second light source, and lying at a distance from the divider screen and from the first coloring means, being associated with only the second light source.